Was reading an engine build-up article [chebbie] the other day and the builder was going to use two different rocker ratios, 1.6 inlet and 1.5 out. Is this common? why would this be done and what are the advantages, if any? would a special cam be needed to match this set up? If there is an advantage could a Y run 1.5-1.4? 

Pete, one of the Aussie mob. Beechworth, Victoria60 F100 Panel Van, Y-block. 65 Galaxie Country Sedan 390